The use of wood and glue to make plywood dates back to the ancient Egyptians (Circa 1500 B.C.). A cedar wood casket found in the tomb of King Tut-Ankh-Amon has ebony veneer with ivory inlay.
In modern times, hardwood and softwood laminate panels have become common and popular structural materials. The softwood plywoods are generally used where strength, stiffness, and construction convenience are more important than appearance while hardwood plywoods are generally used where appearance is more important than strength.
Plywood is made by adhering multiple wood veneers with the grain of at least one veneer at an angle to the grain of another. Other types of structural composites are made by binding chips, flakes or particles of wood into boards or panels.
The adhesives used to bond veneers or bind pieces of wood have evolved from solely plant or animal origin (e.g., hide, bone, blood, casein, soybean and vegetable) to synthetic resins such as urea-formaldehyde (UF) and phenol-formaldehyde (PF). Modern glue mixes for plywood generally include a phenol-formaldehyde resin along with various extenders (e.g. proteinaceous and/or amylaceous materials) and/or fillers, (e.g. cellulosic and/or lignocellulosic materials).
A variety of additives or modifiers for phenol-formaldehyde resins have been proposed. Carbohydrates, particularly those derived from hydrolysis of wood, were proposed and evaluated as modifiers of PF resins for plywood by A. H. Conner et al., "Carbohydrate Modified Phenol-Formaldehyde Resins" Journal of Wood Chemistry and Technology (November 1985). This article discloses that carbohydrates having free reducing groups, e.g. xylose, were unsuitable, but that methyl xyloside and methyl glucoside yielded resins having acceptable bond strengths when used in crude formulation and application methods.